New dynamic microreactor system to mimic biofilm formation and test anti-biofilm activity of nanoparticles

Abstract

Microbial bioflms are composed of surface-adhered microorganisms enclosed in extracellular polymeric substances. The bioflm lifestyle is the intrinsic drug resistance imparted to bacterial cells protected by the matrix. So far, conventional drug susceptibility tests for bioflm are reagent and time-consuming, and most of them are in static conditions. Rapid and easyto-use methods for bioflm formation and antibiotic activity testing need to be developed to accelerate the discovery of new antibioflm strategies. Herein, a Lab-On-Chip (LOC) device is presented that provides optimal microenvironmental conditions closely mimicking real-life clinical bioflm status. This new device allows homogeneous attachment and immobilization of Pseudomonas aeruginosa PA01-EGFP cells, and the bioflms grown can be monitored by fuorescence microscopy. P. aeruginosa is an opportunistic pathogen known as a model for drug screening bioflm studies. The infuence of fow rates on bioflms growth was analyzed by fow simulations using COMSOL® 5.2. Signifcant cell adhesion to the substrate and bioflm formation inside the microchannels were observed at higher fow rates>100 µL/h. After bioflm formation, the efectiveness of silver nanoparticles (SNP), chitosan nanoparticles (CNP), and a complex of chitosan-coated silver nanoparticles (CSNP) to eradicate the bioflm under a continuous fow was explored. The most signifcant loss of bioflm was seen with CSNP with a 65.5% decrease in average live/dead cell signal in bioflm compared to the negative controls. Our results demonstrate that this system is a user-friendly tool for antibioflm drug screening that could be simply applied in clinical laboratories.